1. Field of the Invention
This invention relates in general to apparatus for positioning boards to be fed through board edge cutters. In particular, the Invention relates to a movable support apparatus providing lateral positioning for a board infeed system. The particular boards handled by the board infeed system are called cants, that is, sawed portions of logs which have two substantially parallel surfaces formed at the top and bottom thereof and which have irregular edge surfaces exhibiting wane where wane is described as a defect in a plank or board which is characterized by a board having bark or insufficient wood at a corner or along the edge of a board due to the curvature of the log from which the board was sawed. Systems have been developed to optimize the yield from a particular cant in terms of maximizing the dollar value of the finished boards produced from the cant. Optimization is accomplished, for example, by a cant being optically scanned to determine the location of various edge and surface defects. The defects are removed in further processing of the board in accordance with and controlled by a predetermined computer program. Signals corresponding to the defects as well as predetermined economic and scheduling parameters are processed by a computer to optimize the yield from each cant. Various aspects of such optimization systems are disclosed in the Sanglert U.S. Pat. No. 3,886,372 assigned to the Saab-Scania Aktiebolag of Linkoping, Sweden and the Kohlberg U.S. Pat. No. 3,970,128 assigned to the Saab-Scania Aktiebolag of Linkoping, Sweden. The Sanglert patent discloses a pair of endless belts, one under each end portion of a cant. Each belt extends transversely to the length of the cant and each of the endless belts is driven by a reversible servo that is controlled by the outputs from a computer. Proper coordination of the movements of the two belts causes edgewise rotation and/or translation of the cant to present the cant to a pair of cutters. The cutters are illustrated as two saw blades, each of which is positioned in response to a computer output. The Kohlberg patent discloses a plurality of laterally spaced belt conveyors, all driven from a common drive shaft. The belts are driven so that a cant placed with its length transverse to the length of the belts is carried through a scanning station where the motion of the cant with respect to the belt is arrested while the cant is being scanned, with the arresting being performed by stops. The scanning operation includes establishment of a reference datum line for a particular board. After scanning, the cant moves on the belts toward a number of orienting stops which are positioned with respect to the reference datum line to obtain a particular angular orientation of the reference datum line established in the scanning operation. The particular angular orientation is determined in accordance with a computer program as previously described. The cant is then translated through the edging cutters while being maintained in the orientation established by the orienting stops. Each edge of a board is finished, or edged, by edging equipment. The edge cutters are adjustable and movable relative to one another. The prior art optimization systems for orienting cants with respect to movable edging cutters contemplate the use of variably positioned edging cutters and no provision is made in such systems for moving the infeed apparatus laterally in a direction perpendicular to the infeed line of direction. Fixed position edgers, such as edge saws, which are presently used in a larger number of manually controlled board optimization systems are not adaptable to be used with scanned optimizing systems of the type described above because current scanned optimization systems require lateral movement of both edgers. The edgers for manually controlled optimization systems have one fixed edging equipment, such as a saw, and one variably positioned edging device. The need thus exists for a means to adapt edging equipment having one fixed edging equipment to computer controlled optimizing scanner systems, which ordinarily contemplate moving both edging equipments.